There are four-bar and five-bar, different size of friction hinges. We offer open angle 60, 90 degree friction hinges. Most of friction hinges are made of 304. And the heavy duty is from 45kg to 60 kg according to the thickness of the bars. We offer friction hinge for PVC and aluminum windows. H4182016F8' 4 bar 1. 8mm bottom channel width 2. 0 mm thickness bar 16mm top bar width 8 inch